The present invention relate to a radio telephone set and, more particularly, to a radio telephone set which can be used as a portable set and a vehicle-mounted set.
Recently, a single radio telephone set has been used as both a portable set and a vehicle-mounted, or onboard, set. When a radio telephone set is used as a portable set, it is powered by a battery attached thereto. When the radio telephone set is used as an onboard set, it is powered by a vehicle battery.
A conventional radio telephone set, which will be described later referring to FIG. 1 of the accompanying drawings, has a power supply (PS) terminal and an ignition (IGN) terminal which are connectable not only with the attached battery but also with the vehicle battery. More specifically, when the radio telephone set is used as a portable set, the PS and IGN terminals are connected to the output terminals of the attached battery. When the telephone set is used as an onboard set, the PS and IGN terminals are connected to the terminals of the vehicle battery. Thus, the user must detach the attached battery when using the telephone set as an onboard set. On the other hand, he/she must re-attach the detached battery to the telephone set when using the telephone set as a portable set. This procedure is cumbersome, especially, to those who frequently change the use mode of radio telephone set.